Technical Field.
1. This invention generally relates to devices for sealing tank covers and in particular to a safety device for sealing the cover of a vehicular tanker which is retrofitable over the standard tank cover.
Background Art.
2. Vehicular tankers are used to carry large quantities of liquids such as petroleum fuels, agricultural products, toxic chemicals, and the like. Normally the tanks on the tankers are provided with one or more circular openings in the top most wall of the cylindrical tank. Circular tank covers are provided to cover the circular openings. Generally the covers are hingedly attached at one side and clasped to the tank or opening flange at the other.
Obviously during use, the tanks are subjected to a tremendous amount of stress from the adjusting liquid load. As a result, the tank opening can be temporarily distorted, and the fluid allowed to leak out. Additionally, the vibrations associated with transit, over time, deteriorate the seal between the tank cover and tank opening. It should also be appreciated that whenever a tanker is involved in a vehicular accident, if the tank itself is subjected to any torsions or stress, and the tank openings can be distorted and the contents allowed to leak out. This can be disastrous in the case of petroleum fuels and toxic chemicals and certainly expensive in the case of agriculture products.
The solution to the leakage problem has heretofore simply been to discard the deteriorated cover and replace it with a new one. Unfortunately, this does not correct a leakage problem do to a distorted or damaged opening in the tank itself.
LYNCH, ET AL., U.S. Pat. No. 1,308,794, and HARTER, U.S Pat. No. 1,407,858, both teach conceptually similar tank closures. Here the common concept is the use of a cover including an adjustable sealing means so that the cover can be tightened as necessary to compensate for deteriorating seals. While the prior art covers do have the advantage of an adjustable seal, they are not retrofitable to the standard tanker tank and both are unduly complex for this particular application. Additionally, both of the prior art devices must be previously installed on the tank and consequently are of no use in remedying a leaking tank in the case, for instance, of a vehicular accident.
What is needed is a device which is readily retrofitable on the standard tank cover which serves to tighten the seal between the tank cover and tank opening which can be installed in both emergency and nonemergency situations.
It is therefore an object of the present invention to provide a safety sealing device which is retrofitable at any time to virtually any vehicular tank or tanker.